A star

An A star is a star of spectral type A, white in color, with a spectrum dominated by the Balmer
series of hydrogen. Lines of heavy elements, such as iron, are noticeable
at the cooler end of the range. Main sequence A stars have surface temperatures of 7,500 to 9,900 K, luminosities of 7
to 80 times that of the Sun (Lsun), and masses of 1.5 to 3 solar masses (Msun). Familiar
examples include Sirius, Vega,
and Altair.

A-type supergiants, such as Deneb,
may be as hot as 11,000 K and have masses up to 16 Msun and luminosities
of up to 35,000 Lsun.